The Basics, Port & Polish and Port Matching
- Thread starter BarelyAWake
- Start date
Funny you say that as that is just (pluse a little more lol) what I have thought about our Mr Sumpter!!?? Now about being bonafide I jest dont know lol. Peace sumpter!
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I posted this on another thread, I'll post it here too...
The best bit of advice I can give about porting the engine with a Dremel tool is DON'T touch the piston at all, or the exaust & intake port hights at the piston!! (you can widen the ports a little at the piston.) The top & bottom of those ports (at the piston) control the timing of the intake & exaust & shouldn't be touched!!
The only thing you want to do is 'blend' the ports (case to cylinder) & the 'ports to manifolds' together for a smoother air flow without changing the timing (at the piston)!!!
The best bit of advice I can give about porting the engine with a Dremel tool is DON'T touch the piston at all, or the exaust & intake port hights at the piston!! (you can widen the ports a little at the piston.) The top & bottom of those ports (at the piston) control the timing of the intake & exaust & shouldn't be touched!!
The only thing you want to do is 'blend' the ports (case to cylinder) & the 'ports to manifolds' together for a smoother air flow without changing the timing (at the piston)!!!
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Greetings B.Awake, you suggest to keep intake & exh. port edges sharp and crisp. Somewhere I've read to chamfer the cylinder side so the rings wont have a tendancy to hang up. any thoughts on that will be appreciated.
Been reading a lot of helpfull info here thanks to all for sharing ur expertise.
Been reading a lot of helpfull info here thanks to all for sharing ur expertise.
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casting looks very good n relatively smooth, little gritty in port, BGF Z2-80. inside ports r chamfered, sloppily. how should head gasket fit propperly? mine just creeps over the raised circular portion of head. anyone make their own w flashing or something?
Iam doing the same to the same motor now. I copper coat all the gaskets on these HT motors. I also lap the head and the jug and match the ports.
copper on head too? using any special materials 4 head and/or exh. I' trying not to buy these and pay shipping. ;>)
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No just on the gaskets. I buy a gasket kit that has better gaskets but copper coat will help just about any gaskets on these motors. I also port match the gaskets if they dont match.
TBH - it was more of a worry regarding chipping/flaking the chrome cylinder liner than anything else, dressing these ports by hand will definitely result in a slightly rounded over edge no matter how you try and avoid it... my thought being if tried deliberately it would result in an excessive amount being removed and damage to the liner...
I've yet to hang a ring with any of the motors I've done this with *knock on wood lol* ...I suspect it's more common with drastic oversize porting, something I'm not a fan of, simply 'cause I can't see the point of having a port significantly larger than the manifold that's attached to it. *shrug*
good stuff here,
but yeah, I'm a newbie or nOOb as J/thegreat said LOL,
and yeah sometimes we need to be taught like an 8th grader who's never seen the inside of an engine, because I haven't!!! but I aint skeered!]maybe a glossary of the terms somewhere on here would be good,...
I just got my first build running and have a snow storm locking me in for a few days so, I'm looking to do something while I have the time,
the chain is my main thing now, want to get it to a better length, it's too long now, but I'm afraid one link removed it may be too short, see my pic,...
had a main head bolt issue, (the whole rod, threaded on both ends, came out with acorn nut, had to grind flat spots in the rod just under the threads to get a vice grip to hold so I could tighten it back into the block) may change those out, or should I just let them be untill I need to get in there again,...?
anyway, thanks, us newbies and hack mechanics appreciate it,...
but yeah, I'm a newbie or nOOb as J/thegreat said LOL,
and yeah sometimes we need to be taught like an 8th grader who's never seen the inside of an engine, because I haven't!!! but I aint skeered!]maybe a glossary of the terms somewhere on here would be good,...
I just got my first build running and have a snow storm locking me in for a few days so, I'm looking to do something while I have the time,
the chain is my main thing now, want to get it to a better length, it's too long now, but I'm afraid one link removed it may be too short, see my pic,...
had a main head bolt issue, (the whole rod, threaded on both ends, came out with acorn nut, had to grind flat spots in the rod just under the threads to get a vice grip to hold so I could tighten it back into the block) may change those out, or should I just let them be untill I need to get in there again,...?
anyway, thanks, us newbies and hack mechanics appreciate it,...
Snow storm? Sounds like fun 
All ya prolly need for the engine chain is a half link like this (check proper chain size): Sick Bike Parts & if the engine studs work the way they are - why replace them?
All ya prolly need for the engine chain is a half link like this (check proper chain size): Sick Bike Parts & if the engine studs work the way they are - why replace them?
nice, snow bike,...!
well, that's just it, the last time I pulled a nut, the stud came out with it, and getting it back in was no fun,.... but it's in there now (working I guess) but the next time I go to pull the head if that whole stud come out again I think I should replace it, and if I do, might as well do them all,...? ya think,...?
Just thought Id bump this up, springtime is around the corner and alot of guys are going to start builds, and will be looking for this info.
Thanks BA
Thanks BA
I bought a tube of Permatex brand Ultra Copper high temp RTV sealant, thinking, "Yeah, now I can seal gaskets"
Then I read the label:
NOTE:Not recommended for use on head gaskets or parts in contact with gasoline.
I assumed it would have been gas safe, why would they make it non gas resistant?
I feel like I wasted 8 bucks for not reading the label, surely oldtimer54 you are not using this product are you?
Seems this stuff is unfit for most of a 2 stroke, because most parts come in contact with gasoline.
The best gasket sealer I have had the pleasure of using is Hylomar. It is resistant to nearly everything an engine could come in contact with. Goes on easy using a q-tip dipped in acetone to spread it around. Gaskets never heat seize to the surfaces, and you don't always need to wipe off the old stuff before installing a new gasket in the future. It is not good for head gaskets though.
Head gaskets like Kopper Kote or silver aluminum spray paint as a dressing.
Head gaskets like Kopper Kote or silver aluminum spray paint as a dressing.
Hey, I have plenty of experience with 2 strokes and 4 stroke engines but have never ported, nor port matched before. I'm looking to get the best performance possible out of my new 66cc flying horse, would anyone suggest me giving it a shot? I have a full work shop and arsenal of tools including machinist tools at my disposal.
Go for it, Nitbbe!
Just read and re-read all the threads concerning the work involved, and don't go overboard with the port re-shaping. Common sense would tell you that a much larger port size will flow alot more, and it will, and the engine would end up making awesome power, but quite the opposite can be true. Smaller ports flow at higher velocity and velocity is what "packs the punch". The trick is finding the perfect balance between the two, and that is what nearly all of the members here have done and shared.
The ports really just need a good cleanup that the factory should have done in the first place, and a teeny bit of re-shaping to optimize the perfect balance between size, flow and velocity.
Take your time and enjoy your work!
Just read and re-read all the threads concerning the work involved, and don't go overboard with the port re-shaping. Common sense would tell you that a much larger port size will flow alot more, and it will, and the engine would end up making awesome power, but quite the opposite can be true. Smaller ports flow at higher velocity and velocity is what "packs the punch". The trick is finding the perfect balance between the two, and that is what nearly all of the members here have done and shared.
The ports really just need a good cleanup that the factory should have done in the first place, and a teeny bit of re-shaping to optimize the perfect balance between size, flow and velocity.
Take your time and enjoy your work!
Heck yah, Nit!
Do it!!!
Kick up the compression a tad, clean up the ports, put a pipe on it, get a decent carb, and FIRST, Get a hub adapter!
Disk brakes and front suspension are also a major improvement.
Best
rc
Do it!!!
Kick up the compression a tad, clean up the ports, put a pipe on it, get a decent carb, and FIRST, Get a hub adapter!
Disk brakes and front suspension are also a major improvement.
Best
rc
I already have the springer forks ordered along with a cns carb (probably gonna regret it from the posts i read on here). The engine will be here tomorrow so it will get a good inspection and cleaning inside and out. I'd like to put a pipe on it but exhaust sytems are one of my week points, I know how these little motors love their back pressure. Im kinda shooting for a whizzer style bike so I still need to figure out the exhaust setup.
